Ultrafast electron injection from adsorbates to semiconductor nanoparticles

Xin Ai; Neil A. Anderson; John B. Asbury; Encai Hao; Tianquan Lian

doi:10.1117/12.507205

4 December 2003 Ultrafast electron transfer dynamics from molecular adsorbate to semiconductor nanoparticles

Xin Ai, Neil A. Anderson, John B. Asbury, Encai Hao, Tianquan Lian

Proceedings Volume 5223, Physical Chemistry of Interfaces and Nanomaterials II; (2003) https://doi.org/10.1117/12.507205
Event: Optical Science and Technology, SPIE's 48th Annual Meeting, 2003, San Diego, California, United States

Abstract

Electron transfer (ET) dynamics between molecular adsorbates and semiconductor nanoparticles has been a subject of intense recent interest because of relevance to many applications of nanomaterials, such as dye-sensitized solar cells, molecular electronics and sensors. However, it is still unclear how the charge transfer rate depends on the properties of molecules and semiconductors. In this paper we examine electron injection from Ru and Re polypyridyl complexes to metal oxide (TiO₂, SnO₂ and ZnO) nanocrystalline thin films. Adsorbates with different energetics and electronic coupling are compared to identify molecular properties that influence ET dynamics. Different semiconductor nanomaterials are compared to understand the dependence on conduction band composition and energetics. ET dynamics were found to be biphasic consisting of ultrafast (<100fs) and slower components, with varying partitioning between them and rates of slow components. These kinetics can be well described by a two-state injection model, which includes injection from both unthermalized and thermalized excited states and competition between electron injection and intramolecular relaxation from the unthermalized state. The dependence of ET rates on various molecular and semiconductor properties is also discussed.

Citation Download Citation

Xin Ai, Neil A. Anderson, John B. Asbury, Encai Hao, and Tianquan Lian "Ultrafast electron transfer dynamics from molecular adsorbate to semiconductor nanoparticles", Proc. SPIE 5223, Physical Chemistry of Interfaces and Nanomaterials II, (4 December 2003); https://doi.org/10.1117/12.507205

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